Skype callers in the US can now make free calls via their iPhone following the launch of an application that allows the VoIP service to be used via the phone's web browser.

According to developers SHAPE: "the application is designed especially for iPhone's touch screen and complements the design and interface of Apple's masterpiece".

All iPhone users have to do is log on to skypeforiphone.com

"Noticing the public interest for Skype on iPhone, we decided to develop an application for them", said Igor Berezovsky, the company's CEO. "No tweaks are necessary."

IM+ for Skype is also available for BlackBerry RIM, Windows Mobile Pocket PC, Palm OS, Symbian and J2ME devices. The application works in any network and doesn't require Wi-Fi.

For a limited time IM+ for Skype iPhone version is being offered free of charge to all iPhone users.